Anaerobic Digestion

Domestic-Commercial |  Anaerobic Digestion

Professional Planning & Impletation

We can design & build commercial scale, anaerobic digestion (AD) plants which process food waste to generate renewable energy and a valuable biofertiliser.

Our in-house design & engineering team have a proven track record and years of expertise in food waste management requirements.

We work with local authorities and commercial customers throughout the UK helping from the design stage through to operation.

What is Anaerobic Digestion

Anaerobic Digestion ( AD) is a natural process where plant and animal materials ( biomass) are broken down by micro-organisms in the absence of air.

1. The Anaerobic Digestion process begins when biomass is put inside a sealed tank or digester.
2. Naturally occurring micro-organisms digest the biomass, which releases a methane-rich gas ( biogas) that can be used to generate renewable heat and power; this helps cut fossil fuel use and reduce greenhouse gas emissions.
3.The remaining material ( digestate) is rich in nutrients, so it can be used as a fertiliser.

Many forms of biomass are suitable for Anaerobic Digestion; including food waste, slurry and manure, as well as crops and crop residues. However, woody biomass cannot be used in AD because the micro-organisms can't breakdown the lignin, the compound that gives wood its strength.

Anaerobic Digestion is not a new technology, it has been used in the UK since the late 1800s, but now an increasing number of AD plants are being built in the UK to generate clean renewable energy. Anaerobic Digestion is also used to treat the waste produced in homes, farms, supermarkets and industries across the UK. This helps divert waste from landfill.
Anaerobic Digestion Process


The products of AD are referred to as biogas and digestate. Biogas is a mixture of 60% methane, 40% carbon dioxide and traces of other contaminant gases. The exact composition of biogas depends on the type of feedstock being digested.

Biogas can be combusted to provide heat, electricity or both. Alternatively, the biogas can be 'upgraded' to pure methane, often called biomethane, by removing other gases. This pure stream of biomethane can then be injected it into the mains gas grid or used as a road fuel.


Digestate is made from left over indigestible material and dead micro-organisms. It contains valuable plant nutrients like nitrogen and potassium. It can be used as a fertiliser and soil conditioner.